(a) Field of the Invention
This invention relates to an actuator for liquid ejection, which is adapted to be mounted on a container filling therein a pressurized liquid, and in particular to an actuator for liquid ejection which is capable of ejecting a jet flow of a liquid from a ejection spout by pressing the actuator downward, and at the same time capable of preventing any residual liquid left inside the ejection spout from leaking out of the ejection spout by means of a plug.
(b) Description of the Prior Art
An actuator for liquid ejection comprising a liquid introduction tube, which is adapted to be connected to a spout of a container filling therein a pressurized liquid such as cosmetics, and a ejection spout for ejecting a jet flow of the liquid and communicating with the fluid introducing tube through a fluid-discharging passage is conventionally known.
In the case of this conventional actuator, a fine hole is bored through the upper wall portion of the fluid introduction tube, and this fine hole is tightly covered with a ring-like elastic belt made for example of rubber.
When this actuator is operated to eject the liquid, the liquid is first introduced from the container under pressure into the fluid introduction tube, and then the fluid thus introduced therein is ejected out of the fine hole to push and enlarge the ring-like elastic belt, thereby to form a gap between the elastic belt and the outer surface of the fluid introduction tube, and passes through the gap to the ejection spout to be ejected out.
After the fluid ejection operation of the actuator, the fine hole is tightly covered again by the ring-like elastic belt. However, since the ejection spout is left uncovered, any fluid which is ejected from the fine hole, but remains inside the fluid-discharge passage is naturally exposed to air entering from the ejection spout.
When the liquid to be ejected is of post-foamable nature, it is hardly avoidable to cause the liquid to foam inside the ejection spout. It is also probable that the liquid remained inside the fluid-discharge passage is oxidized thereby degrading the quality of the liquid.
Further, the liquid ejected from the fine hole may be leaked out of the container through a gap formed at the connecting portion between the spout of the container and the actuator.
Since the ejection spout is open at any time, it is hardly avoidable to cause membranous cover to be made thereat and to stop up the spout.